Engine Problem

Hello,

My Hero XTREME registration no:UP 14BV9768. After purchasing the bike within 20 days engine was open due to manufacturing fault. From last one year there is problem of leakage of engine oil. I had showed this bike to hero workshop where I had bought it 6-7 times but every time they change some new part but the problem was not solved and every time said that it is a manufacturing defect so go and make a complaint to company. They say that there is a crack on body. I request you to solve my problem.